Comparison of a Flexible Laryngoscope with Calibrated Sizing Function to Intraoperative Measurements

Abstract

The calibrated endoscope is capable of providing useful sizing information for laryngeal structures, and these measures correspond quite well to more direct measurements in the operating room. Objective sizing of laryngeal lesions is complicated by subjective judgments of lesion boundaries, which can be indistinct in many cases.

Association of breathing sound spectra with glottal dimensions in exercise-induced vocal cord dysfunction

“…A study by Kobler et al in 2006 developed a prototype fiberoptic transnasal laryngeal endoscope with an additional optical system for calibration of images. However, they reported rather high margins of error for lesions with well-defined borders, ranging from 14 to 50% [27]. …”

Development of Laser Ruler in Rigid Laryngoscope

“…In 2006, Kobler et al (5) designed a device that could project 23 individual green standard spots into the field of view of the endoscope by installing a 150-mW green diode laser source within the nasopharyngeal endoscope, and by placing a glass plate printed a lattice scale between the optical fibers and the lens. As a nasopharyngeal endoscope, it can be used even during normal phonation.…”

Adding the third dimension—A new tool for constructing 3D models of the airway from 2D bronchoscopic video

“…These methods, while revolutionary, had limitations with respect to image distortion correction and were very labor intensive. Other work by Kobler et al [5] has demonstrated that individual measurements obtained via flexible bronchoscopic correlate well with endotracheal tube measures. In this study the possibility of automatic distortion correction and 3D rendering of 2D image sequences was examined and developed into a usable technique which was applied to a test case.…”

“…A qualitative point cloud model was then created by applying this analysis to each frame in the sequence. In order to achieve a quantitative model an instrument of a known dimension was placed in the airway and the video analyzed as above [5,7]. The known instrument measurements were then used to apply a scale to the rest of the model.…”

“…Various techniques of creating scale can be used. The use of an instrument of known dimensions worked well although may be replaced by laser distometry which has been demonstrated accurate within 5% [5].…”